Tom Murphy, Associate Professor of Physics, University of California San Diego

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Tom Murphy

Tom Murphy is an associate professor of physics at the University of California, San Diego. He currently leads a project to test General Relativity by bouncing laser pulses off of the reflectors left on the Moon by the Apollo astronauts, achieving one-millimeter range precision.

Murphy's keen interest in energy topics began with his teaching a course on energy and the environment for non-science majors at UCSD. He has explored the quantitatively convincing case that our pursuit of an ever-bigger scale of life faces gigantic challenges and carries significant risks.

Tom Murphy, associate physics professor at the University of California San Diego, projects energy needs in coming generations, and shows the cost of maintaining our current way of living. "The fossil fuel joyride that we have experienced has clouded our judgment," says Murphy.

we're going to begin this point being called rethinking sustainability and first speaker the Tom Murphyassociate professor or physics University of California San Diego the title of his talk is growthhas an expiration date Tom right so it the first slide My name is Tom Murphy andI am a a physics professor at UCSD my day job is seeing a laser tomoon abroad the green leaves with me just to have one of these prompts and measuringthe distance to one millimeter precision as they tested in relativity it's on the cutting edgeof the US and abroad to be but don't worry that's when we're talking about todaywe're talking about something that made the inside more important which is the notion of growthand help what more constraints we can say about this from a certain physics analytical pointof view I'm I can I don't have the power to tell you what that dayis but you get some hints along the way um you know that the theme oftoday's sustainability so this will beg the question of you know what the sustainable mean let'stry to get her head around that concept so um growth in general we assessing theprogress we have a marvelous technological society as a result and we have better quality oflife medical care all these things are fantastic said growth was this it is a verypositive influence in our lives at first email and restrict their attention to physical growth onenergy as a proxy for this and the part that is because um you know aboutenergy we would not have this um this technological society and its at the surplus energybeyond the subsistence level of energy it's the surplus energy that's made more food available that's createda population of surge and the planet lead to more industry and economic growth and adjacentto the foundation behind all that truly today we use energy in the world at arate of twelve terawatts steps the the rate of electricity and onlookers total energy use upand historically that's grown the two to three percent for year so what's this mean ifwe keep expanding and just to show that the growth history this is the United Statesthe blue dots for the data from sixteen fifty to the present and what you seethe red one is an exponential that I'm at two point nine percent for your fitsquite well what's more astounding to me is that you go to logarithmic plot so thatthis is the same data but now in its financial is a straight line in theslog of the top and look how amazingly straight that trade this for centuries it's breathtakingthat were on this exponential trajectory that's a two point nine percent for year three okso what if we continue this this see where this is going at twelve terawatts todayand time into the future this is a actually slightly less steep curve of two pointthree percent for your ID that for its mathematical typing this because that means a factorin every hundred years but many cases slightly less than what we've seen what that doesis in three hundred and thirty six years from now we are using as much poweras all the solar energy the hits all the continents of the landowner so we hadhundred percent coverage of the land not piece of dirt to be seen from the sunhundred percent efficiency of solar panels are meant to mimic when possible where three min thirtysix years but you know we've got more than that without the ocean the buzz isjust a little bit more time um if we want to keep going and put solarpanels all we are in the sun we get up to fourteen hundred years but inour stars of the owners are sons of the list are we had a hundred billionsuch stars in the galaxy twenty five hundred years from now are using as much energyis all the stars and milk the Galaxy at a modest two point three percent growthrate this is the devastation of its financial affairs so if you're stuck in the mindsetof exponential growth you have to realize what the consequences are I say we know we'redoing twenty five hundred years ago I can claim from this that I know of werenot going to be doing twenty five hundred years and were not going to continue thistrajectory up incidentally there of thermodynamics limits to that energy production if you let say younot use the sun and solar energy as up as the example established through let's seethat's the magic few sooner you know even a word that we have yet for someenergy production process on earth um you know in fourteen hundred years were using as muchas the entire sense that means we would have to have as much energy as thesun is pretty now in some fantastical device on earth it's gonna get hot ok andbecause it's smaller than some and effective incarnate son and we can play this game evenif as this would you be the same numbers basically that we're starting with the globalaverage temperature of fifty nine degrees Fahrenheit and all this waste he has to get intospace as a radiance this it's the only way off the planet and so in somethinglike I don't know why the spacing get screwed up when the sun computer by lawI'm ninety nine for her body temperature loss of four hundred years from now we boilthe water on the surface of the planet in the mirror you know four hundred andthirty years or something then you know we keep going and burn paper melt steel andyou now can we get the sun surface temperature less than a thousand years and thisjust their mundane and skinny physicists would tell you the same thing given that the problemset up this way by comparison global warming this is a lot of skills that someof the CD as a very minor it from this I'm not talking about global warmingand sea or two done talking about thermodynamics heat loss from the earth the waist theremoval of waste it so you know what this should tell any reasonable person as thatthe premise here is ridiculous it's absurd to spend Pascoe the premise that we would continuedue to its absolute knots bunkers will not happen there are lots of reasons why we'renot going to do that I mean obviously are not cooked ourselves but um you knowpopulation growth will presumably saturate now it's going to take off some pressure for energy profitcetera I'm instantly and fun at fossil fuels were not in a go much further alongMr so the lesson is that a future president in energy ok I'm most planning Commission'seconomists etc countries this bill that in this assumption expected to grow so does St mywork and short term but you know it's harder on there that we just expect willgrow because everybody we've met and everybody that they've met has experienced this world of crossit's been going for a few years now and we tend to think that even ifok things to level off the population levels awful lot more energy um we can stillmanage growth and certain economic sense because we can still bring up standards of living wecan have efficiency gains technology innovations of these kinds of things to keep marching along butI'm going to make the point and it's maybe a little subtle but those things cannotbecome the whole economy ok there's an energy base underneath all this fundamentally were were physicalbeings living in a physical world where the tide energy and divorcing our economy entirely thisdecoupling from and she is not the best fantasy in me it's not even academically onus so let's just look at a snapshot of growth over the last entry the dotsare the data for the gross world product his entire world and for the first halfof this entry regret about two point nine percent growth rate which it was from thestriking that's the same rate at which energy growth occurred and since nineteen fifteen we hadeconomic growth faster than energy which is maybe often taken as an evidence for this decouplingthat we can grow without energy and we can in fact because on him this isconsidered something of a triumph on but the gap you know and understand what's in thatgap it's partly increased interest efficiency do more with less um any other part is growthin things that are less energy intensive which upon the service sector so you know innovationclerical work real estate um I guess it's um in all the other things that don'treally require a lot of energy on psychotherapy we have to have to cope with thiscrazy world I'm so it's clear that low energy Act it is this not in itfor a second and that those things don't exist and that they can increase on buthow much can the sufficiency of improved let's look at the efficiency part in storage listento any examples like refrigerators in cars that have increased by a factor to inefficiency overthirty five years it's been passed a law for this I'm back to two percent foryour improvement discovered the scale not all examples of such tiny most things in fact don'tgrow that fast these are the shining examples of Carpenter travel something like one percent foryour analyze things are just not going to change its all is going to take tokill a calorie of energy to heat a liter of water one degree C physics tellyou now you not in the door for cheaper than that a lot of things electricmotors party at eighty nine percent efficiency how much more can you improve those I'm livinga family down the road at freeway speeds are always can be fun here that's ananswer to that standard cost um you know trusted Carson single file notwithstanding up and soefficiency is also good to have willingly be one or two bunnies left in him andwe will pull these buttons on a hat on but we can expect that forever casinowe have a hundred percent cap in the end and you know we can maybe geta factor to cross the board I don't think we should anticipate more than about afactor too and someone in Europe the toy model work with a one percent efficiency improvementfor your time for another factor to and this is just a graphic showing up airplaneefficiency um in energy consumption per passenger kilometer for instance overtime and its engine prop planesare here Jets actually initially work less efficiently prop planes patrolling be squeezing turboprop planes wereon and that's a one percent the year improvement now here's a toy model ok thisis the data it's the year but the toy model has energy flattening out does theabove image scale for energy as fighting off but we boost the available energy be usefulin Dubai efficiency gains is to have more than were actually the right and you're goodbut if we want to keep the economy growing five percent there's a growing gap okand so some fraction than increasing fraction of your economy has to be based on lowenergy activities real estate the sky of things and at some point this red dot isover and read index is the percent of the economy it's in the service it doeshave to grow and grow until it approaches a hundred percent and meal of apartments fromhere to the top is how much of your economy depends on energy food manufacturing friendsfor all those things and so my claim is that you're not going to end uptending towards zero UNICEF tree it and that's when economic growth last stop the case ofphysical growth isn't that redundant there are viable mechanisms for growth that doesn't require physical growthnon art and after lots of examples the reach is limited you're not going to tendtoward zero in the energy sector which means that would become free effectively if if thismuch of your economy nine point nine nine nine nine percent of the economy isn't onenergy your energy is basically free it's hardly anything I just don't that's not the worldwith them especially for resource that limited that set them free ok I'm so economic growthwill actually also in insulation acts which have a model for steady state economy it betwice first to do so so to stick with what the population law group that scaleover a very long baseline for a long time we threw in a modest rate thetwo thousand are doubling time but look at this hockey stick that what's happened is thehockey stick and a lover of the plot which is super scary okay um I meannormally I'm just this line would look like a hockey stick in the linear plot it'sbeen a super fit super experimental set near doubling time in recent times us break thatdown a little closer and see their sem break points that are interesting on the firstbreak point on the street corners around time in the investor revolution which well if you'vebeen to call revolution it's not a renovation at school um does anybody know what thefirst use of the steam engine was the first major employment of steam and wanted todo so that pumped water and one seeking a more call this so it was verymuch a cold driven enterprise then we had the green revolution in agriculture which is reallyjust the way to put oil in two and other fossil fuels the fertilizer and anincrease of the streets and what you know you produce more food to produce more peoplesaid all talk listen to him is it's just a reflection to me are of thefossil fuel bill and if we look at fossil fuels over a long term this issort of cartoon we had slaves animals and firewood for energy before then we ran intofossil fuels we don't know what comes after but that the point is that word avery special moment in the history of humanity and we found the hearse battering plugged upLas Vegas from spinning as fast and possibly can um and treating the last two hundredyear history as normal and extrapolating ruthlessly from that as a very perilous it it wasan analysis now this is housing prices up over the last century and Tweed heads andboom and bust cycles and holy cow look of this thing um I have I boughta house and when the mood to send me a ride back here maybe on thecurve singer rocketing up a better day then and then I get really nervous because theRed Center in one of quantitative analysis what's in the hand way the analysis at allreal estate will never be a learning phase of the new now um it's not abubble um same Diego intricately around that house prices will go down to such a desirablemarket I sold my house right there started drinking and turn out the whys and sohere we are on a similar part of the trajectory and fossil fuels we have allthis hubris it's a new now it's a new world I don't know him he couldbe announcing its not but let's not get ahead of ourselves and assume that we're goingto solve this problem because we assume that were in a song that were not workingon it that's that's the danger is this complacency now a lot of people really objectwhen I say that this could be it anything like that every phase and calm thatwe could potentially even consider returning today on a more primitive future this must be whatsaves someone to enter yours now our life joining us now is so unimaginable us justlike people in the team owner could not have a man to Overton today and sowhy should we you know they're trying to bring humility this argument that we shouldn't assumethat we can even comprehend the world who are just now I'm totally great um let'ssay that that future joining us now with love each other over the heads with halfthe bones for protecting your food supply comp who today here in this room would havepossibly conceive the second half right based on where we are in our trajectory so I'mall about humility in the future let's not make it on and justifiably asymmetric based onour recent history um on a finite resource but let's say that we manage the transitionto renewable resource and we can level at our energy ok leveling out actually means thatwe have to live in about fifth of us entered the living today and I saythat because the US has five percent world's population twenty five percent of the energy andinequalities are difficult to justify in the statistic world that Islam is not growth you cansay well the people of the bottom hem growth opportunity once you realize that's not trueinequality becomes a moral issue are difficult to maintain but could we even sustained today's visiblethrough prayer I mean we got twisted promise to trees degradation a rain forests are beingtop soil calling were losing into aquifers being pumped out mineral asked me some energy isnot the only part of a story here and if you want to accomplished the dreamof ever buying world lives like Americans do today it about a ten times increase inour our group and five times just to have today's population that today's standards but Brennahad growth in population and today's standards in the end of the world so that's afact of ten total and compelling but you guys are nice people and get a discountknock a bike and five because we're going to have some official gains whatever but isn'twhat it looks like it makes the fossil fuel era look like it and significant blackand some people say will exact with such just the kick start the B cell umbut what makes us think we can do this when we're not maintaining at one timesvery well so an example a kid might really want a pony morning eating one oftwenty twenty to twenty all your boss Tony has partnered with say ok well let's getit terrible to see and take everything you feed it to clean its cage if youmanage that you get a cat it's more work the litter box it's more needy ifyou can miss that though we get a puppy we'll give you a copy and nomore working on a walk it if you can manage that upgrade to go to ademocratic to take care of in the room was like a farmer if you can bethe go then you get the pony but that's a responsible approach and the problem Isee is that were having difficulty right no one excuse for not taking care of ourjournal we have shown that we can take care of a durable and so what makesthis think that we deserve a pony our wee deluding ourselves but talk about Tony TonyTony Tony that's what we talk back so on do we deserve to be using theword sustainable also because we haven't really understood what it means or what level we canexpect to operate sustainably and it's an open question so I think in my mind thefossil fueled to a right that we experience has better judgment we think that were cleveror smart will really you know with a monkey the stock at stake into that Brownbecame dripping with honey or oil and we were very pleased with ourselves but you knowit's this the innards that's what minutes people were doing now one very quick hit onsomething that I think is a real shorter term were at talked about long term problemsof maintaining growth but let's say that we did do I begin to decline in infossil fuels which I believe for oil happen in the next decade will start to declinein oil content oil availability if we want to build a new energy infrastructure to buildour way out of this problem with their smarts and our technology that requires an upfrontenergy investment to build the infrastructure that's exactly what we're reading short time so we haveto intentionally exacerbate make the problem worse too umm to start down that path and that'spolitically very difficult to do just to put some numbers on it if you develop aresource for the forty year lifetime the windmill solar panel nuclear plant and it delivers somethinglike the fact of ten of the energy they use in but you get a returnthat's ten times when you put in to the pool value for say the solar panelswind might be twenty one but it's in this neighborhood if you want one energy foryour innards unit for your out of this the cost of four units up front Stoopsthe ratio of those two things and the promised there's no energy financing in nature youcan build a windmill on promised energy you gotta have the energy of fraud it sothat you actually steep than the decline and once you start such a program if youare bold enough to do that abandoning that program is always can be too tempting thenext politician can repeal the program and why constantly gets better for the short term soit's very tempting split with heart I'm not going to go over the summary in thehelm of literature and time but you know I just wanna point out again that youknow growth when we should really think about steady state economics in a serious way I'vebeen in the notions of growth as the only way things can go on we haveobserved a pony have we deserve use the word sustainable um there are some real promisewith this tender trap but let's not be led by scientists assumed that we can getpast his promise as if we just assume that we cannot we don't put the realrecesses wheel mitigate the actual risks that could happen ok I'm so when you look atCasa de and sustainability ask is this an idea based on continued growth does this abusethe word sustainable um does this help secure merger will or is it just more promiseup for a pony so on all stop their work or not I've got a newblogger must ease um ideas are expressed there it's fairly recent but it's got him torepeat he's so you can add to that an experiment thank you the equipment about oneone question but it's a question and one and it is not a formal but thankyou very much it